ACE LEAD

If a partnership’s standard lead from A-K against a no-trump contract is the king, the lead of the ace can serve as a request for partner to play his highest card in the suit. You could lead the ace from A-K-J-10-x and find out straight away whether partner has the queen. This is no longer a common method because, with such a holding you would want partner (if unable to unblock) to give a count signal.